Oil well completion



April 4, 1967 Filed March 10, 1965 z QQ OkL H. KOPLIN OIL WELL COMPLETION 2 Sheets-Sheet 1 April 4, 1967 H. KCI)PLIN OIL WELL COMPLET I ONFiled March 10, 1965 2 Sheets-Sheet 2 ggzqm United States Patent 0.

3,312,280 OIL WELL COMPLETION Harry Koplin, 1785 Broad Causeway,

North Miami, Fla. 33161 Filed Mar. 10, 1965, Ser. No. 438,711 7 Claims.(Cl. 166-21) This invention relates to oil well completion techniquesand devices for selectively connecting sections of well casings tovarious strata. In most oil well bores there are zones of permeabilityinterspersed with water sands, shale sands, or non-oil bearing zones orlayers. It is desired that these various non-oil bearing strata all beexcluded from connection to the well output for obvious reasons, andtherefore, it has beenthe practice in some oil well completion methods,after drilling of the well bore, to line .the bore with a casing ofcement, and then to perforate certain portions or strata levels of thecement casing by means of explosive shots, often using nitroglycerin forthis purpose. This cementing and perforating by shooting is oftenunsuccessful ,in obtaining the best results "because sometimes the shotsfracture the cement used to line the casing in the well bore atundesired points. Sometimes also the shots fail to explode or fail topenetrate the cement lining. At other times, the high temperaturesgenerated by the explosive may glaze the surface of the surrounding soilor sand and cause it to become less permeable than is desired. The useof explosives is also hazardous in itself.

Because of the various shortcomings of this method of oil wellcompletion, other techniques have been developed, calling for theinsertion of a tubular metallic easing into the well bore, this casinghaving thereon transversely slidable or extensible strata connectionelements forcibly moved outwardly from the tubular casing by hydraulicpressure applied from within the casing. When extended, these connectionelements are intended to contact with and provide ducts leading topreselected oil bearing strata. In this method the cement is placed inthe annular space between the outside of the casing and the walls of thewell bore by being forced downwardly through the casing and outwardlyinto the annular space surrounding the casing at .the bottom, flowinginto and filling the space from the bottom upwardly to a level above theduct-providing strata connection elements. In this method the connectionelements can be extended hydraulically before the cement is introducedor shortly after the cement is introduced but before it has time to set.In either case, special precautions have to be taken or arrangementsmade to avoid having the cement enter the connection elements and theexcess cement in the tubular casing must be removed in some fashionbefore the well can produce. Any cement inside the casing must beremoved because the final step in establishing connection through theduct-providing connection elements is to dissolve or destroy a closureplug or core in each of the elements by means of chemicals or heatapplied from within the tubular casing and cement in the casing preventsthis. Besides requiring a source of hydraulic pressure at the well site,another drawback in this technique is the need for making all joints inthe casing and betweenthe casing and connection elements sufficientlytight that the hydraulic pressure used will force the connector elementsoutwardly in the proper fashion at the desired time. Otherwise, enoughpressure may not be available to operate all of the desired connectionelements, or some of them may be only partly extended and fail to makeproper contact with the selected portions of the well bore.

The present invention avoids the hazards and difiiculties inherent inthe above-described well completion 3,312,280 Patented Apr. 4, 1967methods, and simplifies the equipment used and its manipulation so thatoil well cementing and completion can be less expensive and more certainthan formerly.

Accordingly, among the objects of this invention are to provide a methodand a tool for completing and cementing an oil well whereby a cementwell bore lining will be kept free from cracks or voids; wherebytransverse connection from a central tube is dependably made to selectedstrata outside of the central tube and the cement well bore lining; andwherein the central tube is kept clear of the cement surrounding thetube. Explosives and hydraulic pressure are not required or used in thismethod or .in the tool for carrying but oil well completion according tothe invention.

One object is to provide a method and means for well completion andcementing in which no special tools or rigs are required other than thecompletion tool itself. Another object is to provide a tool of simpledesign, using a number of standard, readily available structural parts,but one that easily may be adapted or converted in thefield to satisfychanging conditions that may be encountered. A further object is toprovide extendable strata connection elements operated mechanically in adependable fashion from within a tubular well casing, these elementsmaking self-adjustable resilient contact with the well bore. Stillanother object is to trigger the .extension of the connection elementsby the application of acids or other chemically active materials againstchemically destructible spring-holding members in the tubular casing.

These and other objects of the invention are met by providing anelongated hollow casing in the form of a tubular element for insertioninto a well bore and by providing this tubular element with transverselypositioned strata connection elements retracted almost entirely withinthe tube but biased toward ejected positions by spring means withinthetube. The springs are held in compressed condition and the connectionelements are held in retracted position by means of chemicallydestructible elements such as bolts or links made of some metal that isreadily dissolved by an acid or other suitable chemical. Ejection of theconnector elements from the tube is caused by applying a suitablechemical to the destructible elements within the tube so that thesprings are released and will thereafter extend themselves and forciblyeject the connectors from the tube into resilient contact with the wallsof the well bore.

Only after the tool is in this condition, with connectors extended, isthe cemented placed in the space between the outside of the tube and thewell bore, and this placing of the'cement is not done through the insideof the tubular member but only from entirely outside the tube in theannular space at the top of the Well bore surrounding the tube.

After the cement has set, the same acid or other chemical in the casingthat was used to destroy the spring-holding bolts or links (or addedamounts of this chemical, or another chemical) is used to dissolve ordestroy closure plugs in the extendedcstrata connection elements so thatclear passageways are provided in the elements from the strata in thewell, through the cement liner and into the tubular well casing. Theretractable connection elements, their closure plugs, the biasingsprings and the springholding links are preferably designed for easyremoval and replacement in the field before the tool is put into use, sothat changes can be made in any particular tool to suitvariousconditions that may arise.

Other objects, some advantages and further details of that which isbelieved to be novel and included inthis invention will be clear fromthe following detailed description and claims, takenwith theaccompanying drawings in which are illustrated some examples of oil wellcompletion tools embodying the present invention and incroporatingchemically destructible spring-holding elements and other featuresuseful in carrying out the preferred method.

In the drawings:

FIG. 1 is a vertical sectional view of a well bore showing a toolaccording to the present invention inserted therein; a

FIG. 2 is an enlarged transverse sectional view through the well boreand tool of FIG. 1 as if on the line 2-2 thereof;

FIG. 3 is a vertical sectional view of the bore and of the tool as if onthe line 3-3 of FIG. 2;

FIG. 4 is a further enlarged cross-section similar to a portion of FIG.3 but with parts in a dilferent condition and showing cement applied inthe annular space between the outer walls of the tube and the bore ofthe well;

' FIG. 5 is another cross-section like FIG. 4 but showing parts of thedevice in still another condition, and

FIG. 6 is an enlarged view like a portion of FIG. 3 showing a modifiedform of chemically destructible spring-holding element.

The tool Preferred embodiments of a tool useful in carrying out thisinvention are shown in the drawings. Some further modifications of thistool are not illustrated but are described hereafter at appropriatepoints.

As shown in FIG. 1, one or more tool sections 10, each of any desiredlength, are joined to pipe sections 12, which may be any desiredstandard threaded pipe lengths, to form an elongated hollow casing ortubular tool element intended to be inserted lengthwise into a well boreW. The body of the tool section may be square in cross section as shown,or it may be round. This elongated tube, with as many tool sections andas many pipe sections as required, is preferably tightly closed at thebottom and open at the top. In the example shown, at the top and bottomof each tool section 10 is an end plate 14, carrying a threaded pipefitting 16 adapted to be coupled to the end of a pipe section 12. Theend plates and fittings may be welded together and to the tool section.For purposes that will appear later, the end plates may also carry anumber of radially extending feeler arms 18, and the outer ends of thesearms may or may not be joined by a guard ring 20 to hold the outer endsof the feelers in proper position. Welds again may be used to hold theseparts together.

At selected spacings along each tool section a number of oppositelypositioned holes are provided, in each of which is suitably secured aninternally threaded fitting 22. Each fitting threadedly receives anoutside threaded shouldered'nut 24, having an inner smooth bore 26 thatslidably receives a laterally extendable member shown as a sleeve 28. Asuitable sealing ring 30, between the shoulder on nut 24 and the end offitting 22, may be used to make a fluid-tight joint between thesemembers. A similar ring 32 of O-shape, located in a groove inside thenut 24, may provide a sliding fluid-tight joint with the sleeve 28 Theouter end of each slidable sleeve 28 is closed as by a removable closuremember 34, threadedly received at the end of the sleeve, and having acore or plug portion 36, made of zinc, magnesium, aluminum, or othermetal or material that is easily dissolved or destroyed by an acid orother chemical. The rest of the assembly abovedescribed, including thepipe sections and tool body sections, is made of iron, steel or othermaterial that is not destroyed by the application of the acid or otherchemical that will destroy the plug. If desired, the entire closuremember 34 may be made out of chemically destructible material like theplug portion, in which case the plug need not be a separate element.

In order to make a seal with the bore of the well, when the slidablesleeve is extended outwardly from the tool as will be later describedunder operation of the tool, the outer end of each sleeve carries acup-like gasket 38 made of neoprene, rubber, or similar resilient andacid resistant material. In the example shown, this gasket is heldagainst a shoulder 40 on sleeve 28 when the closure member 34 is screwedinto place. The free outer edges of the gasket extend beyond theoutermost end of the closure 34 and its plug portion 36 to make sealingcontact with the wall of the well bore before these elements aredestroyed. In some situations the gaskets may not be required and inthose cases the outer faces of the closure members and of thedissolvable plug are contoured to match the curvature of the well boreto form a tight fit with the well bore when the sleeves are extended.

When the tool is assembled prior to insertion into a well, the slidablesleeves of each pair are positioned inwardly of the tool as far aspossible so that their outer ends project a minimum distance therefrom.Friction of the sealing rings 32 holds the sleeves in this retractedposition. It should be noted that, when both sleeves of a pair of thesleeves 28 are fully retracted, as shown in FIGS. 2 and 3 for example,there remains a clear space 42 between the inner ends thereof, thisspace lying near the axial center of the pipe sections 12 and toolsections 10 of the hollow elongated tool.

Spring means are provided to extend the sleeves transversely outwardlyof the tool at the proper time and to hold the outer ends of the sleevesresiliently in sealing contact or engagement'with walls of the wellbore. Shown here is a compression spring 44, located within both sleeves28 of a pair, this spring in fully extended condition spanningthe spacebetween the inside of the closure member 34 of one sleeve 28 and theinside of the closure member of the opposite sleeve of the pair, thespring extending the sleeves outwardly to their fullest extent andpressing the outer ends of both sleeves into firm engagement withportions of the walls of the well bore. This position or condition ofone sleeve is shown in FIG. 4.

Obviously, it is not desired that the sleeves be extended while the toolis being positioned within the well, and to keep them in their retractedposition each of the springs 44 is compressed to a length less than thespace between the closure members of a pair of the sleeves when inretracted position. The compressed spring is held in this condition by alink or bolt 46 and end nuts 48, as shown in FIG. v3. Thisspring-holding link (and the nuts, if used) is of chemicallydestructible material similar to or the same as that of the closureplugs 36. FIG. 6 shows a different form of destructible springholdinglink in the shape of a tube 50 with flared ends 52 engaging the ends ofa compressed spring 44.

Whether the destructible spring-holding link takes one form or another,its central portion, and the central part of the spring that it holds,extends across the clear space 42 between a pair of retracted sleeves,lying generally in the longituidnal axis of the hollow elongated tool.'Adjacent pairs of the sleeves, which may be located as close togetheras three inches, are preferably positioned at right angles to each otheras shown, so that when the sleeves in a tool assembly are extended theywill center the hollow elongated tool in a well bore and provide anannular space A in the bore surrounding the .tool on all sides. Thiscentral location of all the links, in the clear spaces 42 between theretracted connection sleeves, makes it easy to apply acid or otherdestructive chemicals to the links.

Using the tool The well hole is drilled in any desired fashion and thebore washed clean if necessary. A log is made, using core samplings orelectronic logging equipment or other methods to determine the locationof potential production strata or zones S or levels at which it will bedesired to make connection. There will be other levels X at Whichconnections definitely will not be desired, and the locations of thesealso will be determined by the well log.

Knowing the levels at which connections to strata S are desired, incarrying out the preferred method of this invention a tool asabove-described will be prepared, having plain pipe sections 12 coveringthe well levels X that are not to be connected, and tool sections withappropriate pairs of extendable sleeves 28 at the desired production orconnection levels. If extensive production zones are found, the lengthand number of tool sections 10 may be increased accordingly, and as manysets of crosswise pairs of the sleeves 28 be provided as are desirableto handle the expected flow.

In one method of using the tool, the feelers 18 may not be provided, buta relatively thin metal protective casing with open bottom (not shown)is placed in the well bore and the tool is then carefully lowered intothe casing to the bottom of the well so that the sildable connectionelements are positioned opposite the perdetermined locations forconnection to the strata S. The protective casing is then removed, iffollowing this method, and further steps followed as explained below.

In a variation of the method, not requiring the protective casingdescribed immediately above, feelers 18, with or without the guard rings20, are provided as part of the tool assembly and the tool is loweredinto the well bore to the bottom or until the slidable sleeves arelocated opposite the potential production strata. In place of the feelerarms 18 other guiding and centering arrangements might be used for thetool, these having also the function of protecting the projecting partsof the sleeves 28 from being damaged while the tool is "being loweredinto proper position in the well. Discs or fins may be provided insteadof the feeler arms 18 and these should extend radially outwardly farenough to protect the ends of the retracted slidable sleeves, but notfar enough or through sufiicient area to impede the subsequent placementof cement in the annular space A as explained below. As shown, the outerdiameter of the main body of the tool is substantially less than theinner diameter of the well bore at any point.

After insertion and proper positioning of the tool within the well byeither of the methods above-described, an appropriate link-dissolvingacid or other link-destructive chemical is introduced through the opentop end of the tool and the spring-holding links will be attacked anddestroyed. As each link loses its holding power, the spring held by thatlink will extend itself, forcing apart the opposite sleeves between andwithin which it is located and resiliently pressing the outer ends ofthe sleeves into sealing engagement with the opposite walls of the wellbore on either side of the tool. The spring, of course, is made of amaterial not affected, by the destructive chemical. By proper selectionof the link material, its cross-section, and the nature andconcentration of the destructive chemical, a wide range of time ofoperation of the springs can be obtained, suitable to many differentconditions or requirements. Because the nuts 24, the assemblies of theslidable sleeves 28, the closure members 34, the plug portions 36, andthe springs and holding links are all removable and replaceable beforeuse, various combinations of sizes and properties of these parts may bemade in the field when preparing a tool to suit different wellconditions that may be encountered in any particular case.

If the same metal is used for the spring holding links as is used in theend plugs, and the same acid or chemical is used to destroy both linkand plug, the metal of the links should be no more than about one-thirdthe thickness of the metal of the plugs, so that the plugs 'are notdissolved at this point and the ends of the springs, when released, willhave sufficient material against which to press to extend the slidablesleeves. Of course, if a differtn material is used for the destructibleplugs, and one that is not destroyed by the link-dissolving chemical,then 6 differences in thickness of link and plug'are not significant,but a second chemical must be introduced at the proper stage and in theproper amount to destroy the plugs.

Having properly located the tool in the well bore and having extendedthe sliding strata-connecting sleeves by applying the link-destroyingacid or chemical within the tubular tool, the equipment is in thecondition shown in FIG. 4, but the annular space surrounding the tool isempty. The next step is to fill this annular space with cement C. Thisis done by using a relatively fine fluid slurry and pouring or pumpingthe cement slurry from the open top of the well around the tool,entirely outside of the tool. If necessary, the cement may be forcedinto this annular space and around and between the extended strataconnecting sleeves by using a small diameter tubing of a size to fitwithin the available space outside the tool, withdrawing the tubing asrequired and vibrating or tamping the cement if necessary as the spaceis filled up. Because the bottom end of the tool is closed and theconnection sleeves are sealed by their O-rings and at the well walls bythe cup-like gaskets, no cement should enter the tool and the ends ofthe sleeves where they contact the well bore should be free from cement.When the cement is at a level above the topmost strata that is to beconnected, cementing can be stopped, and the cement is allowed to set.This is the condition shown in FIG. 4.

During the time the cement is being applied and is setting, the acid orother chemical in the tool may be working on the destructible plugs inthe ends of the extended strata connecting sleeves. In one arrangementthat has been found satisfactory, zinc plugs were used, and zincspring-holding links, the plugs being of a thickness calculated to beeaten out by means of an acid introduced into the tool in a period ofabout 72 hours after the well was cemented. This gives ample time forthe cement to set, and after the plugs are destroyed the entire tubingforming the tool may be swabbed out or the spent acid neutralized byintroducing a suitable neutralizing base into the tool. If preferred,water under pressure may be put into the pipe section at the top of thetool and the spent acid can be injected into the oil bearing sands, whenacid injection seems to be indicated for the purpose of startingproduction. If the connected well formations can produce by natural orartificial pressure, the well is now ready for use. Each of the extendedsleeves now provides a clear passageway from a preselected stratum,through the cement liner and into the central tubular casing formed bythe tool. The cement liner effectively seals off strata to which noconnection is deisred, prevents collapse of the well bore, andreinforces the central casing against excess pressure damage. FIG. 5shows the tool after cementing and after destruction of the closureplugs.

The tool and method above-described have been found to be useful for thecementing and completion of oil well bores having depths of the order of3,500 feet and less and diameters of about 9 inches. These sizes,although given as practical limitations with the materials and equipmentpresently available, are not to be considered as limiting the invention.Also, as will be evident from the foregoing description, certain aspectsof this invention are not limited to the particular details set forth asexamples, and it is contemplated that various and other modificationsand applications of the invention will occur to those skilled in theart. It is therefore intended that the appended claims shall cover suchmodifications and applications as do not depart from the true spirit andscope of the inventron.

What is claimed and is desired to be secured by Letters Patent of theUnited States is:

f1. An oil well completion method comprising the steps 0 placing into awell bore an elongated tubular casing of smaller diameter than saidbore, leaving an annular space between the outside of said casing andthe walls of said bore, next resiliently forcing opposite pairs ofextensible tubular connector members laterally outwardly from saidtubular casing, to span said annular space at selected points in saidbore located 'at levels corresponding to strata in the well bore to beconnected to said casing, the outer ends of said connector members, whenextended, making sealing contact with said strata and carryingchemically destructible closure plugs therein, then filling the saidannular space and around each of the extended said connector memberswith a sealing cement by introducing the cement downwardly into saidannular space from the top thereof and entirely outside of said casing,

allowing the sealing cement to set, and finally destroying the closureplugs in said connector members by the application of chemicals theretointroduced from the inside of said tubular casing,

whereby passageways are opened from said strata through said connectormembers and into said tubular casing.

2. An oil well completion method according to claim 1 in which the stepof resiliently forcing opposite pairs of said extensible tubularconnector members laterally outwardly is performed by first compressingspring means between said connector members and holding said springmeans in compressed condition by a chemically destructible springholdinglink and then releasing said spring means from said holding link by theapplication of chemicals to said link to destroy the same,

whereby the released spring means will resiliently force said connectormembers outwardly.

f3. An oil well completion method comprising the steps placing into awell bore an elongated tubular casing of smaller diameter than saidbore, leaving an annular space between the outside of said casing andthe walls of said bore, next chemically releasing a spring means andthereby resiliently forcing an extensible tubular connector memberlaterally outwardly from said tubular casing, to span said annular spaceat a selected point in said bore located at a level corresponding tostratum in the well bore to be connected to said casing, the outer endof said connector member, when extended by said released spring means,making sealing contact with said stratum and carrying a chemicallydestructible closure plug therein, then filling the said annular spaceand around the extended said connector member with a sealing cement byintroducing the cement downwardly into said annular space from the topthereof and entirely outside of said casing,

allowing the sealing cement to set, and

destroying the closure plug in said connector member by the applicationof a chemical thereto introduced from the inside of said tubular casing,

whereby a passageway is open from said stratum through said connectormember and into said tubular casing.

4. An oil well completion tool comprising an elongated hollow casingadapted for lengthwise insertion into the bore of a well,

a connector sleeve slidably mounted in a wall of said casing forextension transversely outwardly of said casing at a preselectedlocation corresponding to stratum in the well bore to be connected tosaid casing when said casing is in said well,

means at the outer end of said connector sleeve adapted for sealingengagement with the well bore when said sleeve is extended from saidcasing,

a plug in said'connector sleeve of a material readily destroyed by achemical, said plug closing the outer end of said sleeve until destroyedby application of said chemical thereto,

a retractable spring in said casing extending adjacent said connectorsleeve, said spring, when extended, forcing said sleeve transverselyoutwardly of said casing and into resilient engagement with the wellbore, and

a holding link for said spring of a material readily destroyed by achemical, said link holding said spring in retracted condition andagainst extension thereof until destroyed by application of saidchemical,

whereby upon introduction of a destructive chemical to the interior ofsaid casing, said link is destroyed and said spring is released toextend said connector sleeve outwardly into engagement with the bore ofthe well and said plug in said sleeve is destroyed to establishconnection of a preselected stratum to said casing.

5. An oil well completion tool comprising an elongated hollow casingadapted for lengthwise insertion into the bore of a well,

pairs of oppositely directed tubular connector members slidably mountedin the walls of said casing for retraction therein and extensiontransversely outwardly of said casing at preselected locationscorresponding to strata in the well bore to be connected to said casingwhen said casing is in said well,

means at the outer ends of said connector members adapted for sealingengagement with the well bore when said members are extended from saidcasing,

closure plugs in said connector members, of a material readily destroyedby a chemical, said plugs closing said members until destroyed byapplication of said chemical thereto, a

a retractable spring in said casing extending between the oppositemembers of each pair of connector members, each said spring, whenextended, forcing the associated members of each pair apart andoutwardly into resilient engagement with the well bore, and

a holding link for each spring of a material readily destroyed by achemical, each link holding a said spring in retracted condition andagainst extension thereof until destroyed by application of saidchemical,

whereby, upon introduction of a destructive chemical to the interior ofsaid casing, said links are destroyed and said springs are released toextend said connector members outwardly into engagement with the bore ofthe well and said plugs in said members are destroyed to establishconnection of preselected strata to said casing.

6. An oil well completion tool according to claim 5 wherein adjacentpairs of said slidably mounted tubular connector members are positionedtransversely of said casing at with respect to each other along thelength of the tool.

7. An oil well completion tool comprising an elongated hollow casingadapted for lengthwise insertion into the bore of a well,

pairs of oppositely directed tubular connector members slidably mountedin the walls of said casing for retraction therein and extensiontransversely of said casing at preselected locations corresponding tostrata in the well bore to be connected to said casing when said casingis in said well,

resilient means around the outer ends of said connector members adaptedfor sealing engagement with the well bore when said members are extendedfrom said casing,

closure plugs in said connector members, of a material readily destroyedby a chemical, said plugs closing the ends of said members untildestroyed by application of said chemical thereto,

retractable spring in said casing extending within and between theopposite members of each pair of connector members, each said spring,when extended, forcing the associated members of each pair to slideapart and outwardly into resilient sealing engagement with the wellbore,

a holding link for each spring, of a material readily destroyed by achemical, each link holding a spring to the interior of said casing,said links are first destroyed and said springs are released to extendsaid connector members outwardly into engagement with the bore of thewell and thereafter said plugs in said members are destroyed toestablish connection of preselected strata to said casing.

References Cited by the Examiner UNITED STATES PATENTS 2,775,304 12/1956Zandmer 166-100 3,087,552 4/1963 Graham 166243 3,120,268 2/1964 Caldwelll66100 3,196,949 7/1965 Thomas 166l00 3,245,472 4/1966 Zandmer 166100CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner.

1. AN OIL WELL COMPLETION METHOD COMPRISING THE STEPS OF PLACING INTO AWELL BORE AN ELONGATED TUBULAR CASING OF SMALLER DIAMETER THAN SAIDBORE, LEAVING AN ANNULAR SPACE BETWEEN THE OUTSIDE OF SAID CASING ANDTHE WALLS OF SAID BORE, NEXT RESILIENTLY FORCING OPPOSITE PAIRS OFEXTENSIBLE TUBULAR CONNECTOR MEMBERS LATERALLY OUTWARDLY FROM SAIDTUBULAR CASING, TO SPAN SAID ANNULAR SPACE AT SELECTED POINTS IN SAIDBORE LOCATED AT LEVELS CORRESPONDING TO STRATA IN THE WELL BORE TO BECONNECTED TO SAID CASING, THE OUTER ENDS OF SAID CONNECTOR MEMBERS, WHENEXTENDED, MAKING SEALING CONTACT WITH SAID STRATA AND CARRYINGCHEMICALLY DESTRUCTIBLE CLOSURE PLUGS THEREIN, THEN FILLING THE SAIDANNULAR SPACE AND AROUND EACH OF THE EXTENDED SAID CONNECTOR MEMBERSWITH A SEALING CEMENT BY INTRODUCING THE CEMENT DOWNWARDLY INTO SAIDANNULAR SPACE FROM THE TOP THEREOF AND ENTIRELY OUTSIDE OF SAID CASING,ALLOWING THE SEALING CEMENT TO SET, AND FINALLY DESTROYING THE CLOSUREPLUGS IN SAID CONNECTOR MEMBERS BY THE APPLICATION OF CHEMICALS THERETOINTRODUCED FROM THE INSIDE OF SAID TUBULAR CASING, WHEREBY PASSAGEWAYSARE OPENED FROM SAID STRATA THROUGH SAID CONNECTOR MEMBERS AND INTO SAIDTUBULAR CASING.